Drive mechanism for mixing device

ABSTRACT

An undulating mixing device for precise, controlled agitation of sensitive biological and chemical solutions provides a base and a platform connected by four flexible connectors, a spring loaded motor mount assembly pivotally attaching a motor to the base, a turntable rotatably attached to the base, a tilt assembly pivotally and rotationally attached to the turntable and rigidly affixed to the platform, and a motor shaft that engages a groove on the turntable for causing rotation thereof. The tilt assembly includes an adjustable collar which controls the tilt or yaw movement of the platform as the motor effects rotation of the turntable. A selectively adjustable speed control switch sets the desired rotational speed of the motor via a microprocessor. The device functions without modification on a plurality of selected voltages and frequencies for achieving the desired rotational speed.

This is a continuation of and claims benefits under pending priorapplication Ser. No. 11/013,875 filed 16 Dec. 2004, now U.S. Pat. No.______.

FIELD OF THE INVENTION

The invention herein pertains to an undulating mixing device and amethod for agitating various solutions in a laboratory environment.

DESCRIPTION OF THE PRIOR ART AND OBJECTIVES OF THE INVENTION

Lab technicians frequently have to agitate, stir or blend very delicatesolutions in a smooth fashion without the introduction of bubbles orfroth where vigorous agitation may ruin the samples, such as duringprotein, DNA and RNA staining operations and processes.

In recent years, several devices have been promoted which gently agitatesolutions for use in laboratory environments and automate tediousprocedures. U.S. Pat. Nos. 4,702,610; 4,893,938; and 5,423,603, areexamples of devices that utilize a gentle vertical agitation forsolutions having components with different specific gravities in orderto prevent layers from forming which may inhibit the completion of adesired chemical reaction. A mixing device having a small footprint, aselectively tiltable platform, and manual speed control, such as in U.S.Pat. No. 5,921,676, addresses the two main problems including (1) arelatively large footprint that limits the number of devices that mayfit in controlled laboratory environments, such as in an incubator or arefrigerated unit, and (2) a predetermined degree of tilt between theplatform and the base that remains fixed during agitation which may betoo pronounced or too little for specific mixing requirements.

Not addressed by these prior devices is the increased possibility ofcontamination of very delicate solutions from the mechanical operationsuch as dust and arcing created by a brush motor along with undesiredvibration and noise. Such contamination may lead to undesired results orinadvertent reactions with the delicate solution.

Additional problems associated with prior mixing devices involve speedcontrol. First, prior devices utilizing mechanical gears to effectadjustment to the mixing rate are more likely to introduce undesiredcontaminants and vibration, but are limited to pre-set gear ratios witha speed control. The problems associated with pre-set speed adjustmentsis they usually do not compensate for the possible varying mass andinertia generated by different load sizes, shapes and placements.Accordingly, the agitation rates of subsequent loads set to the samespeed may differ from that of a prior load despite having the same speedcontrol setting. The different actual agitation rates may causeundesired results and variations of the sample solutions.

Thus, with the above concerns in mind, it is an objective of the presentinvention to provide a laboratory mixing device with an electronicallycommutated brushless motor to prevent arcing, possible contamination,and vibration associated with a non-brushless motor.

It is another objective of the present invention to provide a laboratorymixing device that monitors and adjusts the actual motor rotationalspeed to a speed desired by the user.

It is yet another objective of the present invention to provide alaboratory mixing device that effects rotation of a turntable via afriction ring within a groove on the turntable for smooth, positivemovement.

It is a further objective of the present invention to provide alaboratory mixing device that will automatically adjust the inputvoltages to accommodate domestic 120 VAC and foreign 250 VACenvironments at 60 Hz and 50 Hz without circuitry reconfiguration.

It is still a further objective of the present invention to provide alaboratory mixing device which is compact, durable and can be costeffective to produce and operate.

It is another objective of the present invention to provide a laboratorymixing device that has low heat contribution to special environmentssuch as incubators and refrigerators.

Various other objectives and advantages of the present invention willbecome apparent to those skilled in the art as a more detaileddescription is set forth below.

SUMMARY OF THE INVENTION

The aforesaid and other objectives are realized by providing a mixingdevice and method for precise, selectively controlled agitation ofsensitive biological and chemical solutions in a laboratory environmentthrough electronic commutation of a brushless DC motor.

The preferred mixing device includes a drive mechanism attached to abase. The drive mechanism includes a brushless DC motor with a verticalmotor shaft having a friction ring affixed in a groove thereon, a motormount assembly for pivotally attaching the motor to the base, aturntable with a central shaft rotationally attached to the base androtated by the motor shaft engaging, a platform, a tilt assemblypivotally attached to the turntable that is rotatable thereunder andrigidly affixed to the platform thereabove, electrical circuitryincluding a pair of circuit boards with a microprocessor in electricalcommunication with the motor for managing the power supplied thereto andthe speed thereof, and a potentiometer serving as a manually adjustableincremental speed control switch through rotation of its shaft. The baseis connected to the platform by a plurality of flexible connectors andthe tilt assembly. Selective electronic activation of the drivemechanism induces rotation of the turntable which carries the tiltassembly about the turntable shaft and while the fluctuating compressiveand tensile forces on the flexible connectors allow the platform to tiltor yaw during rotation as the tilt assembly pivots back and forth abovethe turntable.

While the base includes a planar portion and a housing, the platform ispreferably a rigid material in a generally planar shape. A commerciallyavailable rubberized non-slip pad can be placed on top of the platformto increase frictional engagement therewith and to prevent the slidingof beakers, dishes, or other containers. While an X-shape is preferredfor the housing, other shapes that form corners allowing the flexibleconnectors to attach thereon to the planar base portion are alsocontemplated. The flexible connectors are preferably a flexiblepolyvinyl chloride tubing although other standard flexible connectors ofeither polymeric, natural or other spring materials are contemplated.The turntable is preferably a rigid disk that defines a circular groovewith an outer wall and an oval pivot channel and is driven by a motorshaft.

The pair of circuit boards are affixed to the planar base portion andcomprise a power control circuit board for converting and regulating thepower supply that is in electrical communication with a motor controlcircuit board for managing the speed of the motor. Functions of thesecircuit boards may be combined into one board or further distributed toadditional boards. The mixing device can accommodate both domestic 120VAC and foreign 250 VAC at 60 Hz and 50 Hz without modification andremains in a powered “on” state when in electrical communication with anadequate power source.

The motor mount assembly includes an arm that is rigidly attached to themotor, a shaft that is rotationally attached to the planar base portion,and a spring which links the arm to the planar base portion wherebypivoting the arm inwardly stretches the spring and moves the attachedmotor arcuately above and across the planar base portion. Pivoting themotor mount arm inward allows the turntable groove to receive the motorshaft while the recoil forces of the stretched spring maintain contactbetween the friction ring and the turntable groove outer wall.

The tilt assembly is a multi-component unit which includes a pivot shafthaving a pivot slot that receives a connecting rod that is affixed tothe turntable, a collar, a ball bearing that is pressure fitted on thepivot shaft and is rigidly attached to the collar which allows thecollar to rotate freely about the pivot shaft, a threaded post that issurrounded by the collar, and an internal spring which rests on thefloor of the collar and abuts the interior surface of the threaded postto prevent any drift thereof during rotation. The tilt assembly ispivotable on the connecting rod affixed to the turntable in theturntable pivot channel. The threaded post is rigidly affixed to thecenter of the platform thereby the tilt assembly links the platform tothe turntable such that selective manual clockwise or counter-clockwiserotation of the collar either raises or lowers the threaded post thereinand thus changes the distance between the platform and the base wherebyan increase in distance decreases the possible pitch and yaw of theplatform and therefore allows for selective adjustment of the verticalagitation induced into the solution thereon during use of the mixingdevice.

The motor is controlled by a microprocessor on the motor control circuitboard possessing pulse-width modulation (“PWM”) module with applicationsoftware-implemented functions that provides (1) a compensated feedbackalgorithm to effect precise speed control including compensation of theeffects of mechanical inertia and loading, and (2) a virtual powerswitch that eliminates routing line voltage carrying conductors to acombination potentiometer-switch assembly which keeps voltage low. Themicroprocessor compares the input voltage received from thepotentiometer, which is a digital representation of the angular positionof its shaft and the selected speed of the motor, and the feedbackvoltage from the Hall-effect sensor array, which is a digitalrepresentation of the motor shaft speed as each sensor provides theinstantaneous angular position of the motor shaft in relation to eachphase of the stator windings, to a table of speed equivalent voltagespre-programmed in the microprocessor and determines the appropriatechange in motor shaft speed direction and magnitude. The microprocessorimplements a change in motor speed by sending output voltage to themotor through the PWM module which regulates the frequency and durationof the output voltage sent to the motor's phased stator windings forelectronic commutation of the motor. In order to provide smooth andgradual speed transitions, the microprocessor directs stepped speedadjustments in the direction of the selected motor speed whereby themagnitude of each step is limited by a pre-programmed maximum incrementor decrease in motor speed. The microprocessor continues to monitorinstantaneous motor shaft speed and direct appropriate successivestepped gradual changes therein to achieve and maintain the selectedspeed.

The preferred method of mixing closely follows the function of thedevice described herein. To begin mixing with the device, the mixingdevice must first be in electrical communication with an electric powersource though a standard electric power cord. Prior to connecting thedevice to a power source, the potentiometer shaft should be placed in afully counter-clockwise position to prevent undesired movement of theplatform and the desired range of vertical agitation should be set byselective manual counter-clockwise or clockwise rotation of the tiltassembly collar. Upon connection to the power source, the line operatedswitch-mode power supply circuit on the power control circuit boardcleans the potentially poorly regulated and unstable plurality ofelectric currents and voltages supplied to the mixing device andconverts the current into +12 VDC which is supplied to the motor controlcircuit board. The voltage sub-regulator circuit contained on the motorcontrol circuit board converts the +12 VDC received into constant andprecise +5 VDC to drive the microprocessor on the motor control circuitboard which manages the motor speed. With power supplied to themicroprocessor, the mixing device is in a powered “on” state and able tomix solutions placed thereon.

Rotating the potentiometer shaft clockwise from a fullycounter-clockwise position increases the voltage sent to themicroprocessor from a ground baseline voltage whereby the potentiometervoltage digitally represents the angular position of the potentiometershaft and the selected motor shaft speed. Provided the voltage receivedfrom the potentiometer exceeds a pre-programmed threshold voltage, themicroprocessor sends output voltage to illuminate an LED proximate thepotentiometer on the base to indicate a virtual “on” state until thevoltage received drops below the threshold voltage.

The microprocessor compares the voltage input from the potentiometer andthe feedback voltage from the Hall-effect sensor array to apre-programmed table of speed equivalent voltages and determines how themotor shaft speed needs to be adjusted. The microprocessor instructs thePWM module to effect the appropriate change in commutation limited inscope by the maximum incremental step whereby the PWM module regulatesthe frequency and duration of the voltage sent to the motor's phasedstator windings and adjusts the speed of the motor shaft towards that ofthe selected speed. The microprocessor continues to monitor and managethe motor shaft speed and directs the appropriate step towards achievingand maintaining the selected speed.

Once the microprocessor receives input voltage from the potentiometerthat exceeds the threshold power “on” voltage, the microprocessordirects the electronic commutation of the motor and the motor starts tospin. The motor shaft and the friction ring preferably rotate at thesame rate. Rotation of the friction ring imparts a tangential force onturntable groove outer wall which causes the turntable to rotate aboutits central axis on the turntable shaft. The rotating turntable carriesthe tilt assembly and the attached platform about the turntable shaftwhereby the tilt assembly allows the attached platform to trace anon-rotational orbit above the base as the pivot shaft rotates withinthe ball bearing. The platform orbiting above the base changes thetension and compression forces placed on the flexible connectors whichaffects their degree of straightness and causes the tilt assembly topivot on the connecting rod and wobble back and forth in turntable pivotchannel whereby the platform tilts or yaws in relation to the movementof the tilt assembly. The movement of the platform provides bothvertical and horizontal agitation of the solutions placed thereon. Asthe potentiometer shaft is manually selectively rotated clockwise orcounter-clockwise to adjust the desired agitation rate, the degree ofvertical and horizontal movement of the platform increases or decreasesrespectively. Agitation will continue until the voltage input to themicroprocessor drops below the pre-programmed threshold voltage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a right side perspective view of the mixing device of thepresent invention;

FIG. 2 shows an exploded isometric view of the preferred mixing device;

FIG. 3 illustrates a schematic partial top view with the turntableremoved of the base of the mixing device;

FIG. 4 depicts a partial elevational cross-sectional view of theturntable of the mixing device;

FIG. 5 demonstrates an isometric cross-sectional view of the turntableof the mixing device;

FIG. 6 depicts a circuit diagram for a line operated switch-mode powersupply circuit of the drive mechanism of the mixing device;

FIG. 7 illustrates a circuit diagram for a +12 VDC to +5 VDC voltagesub-regulator circuit of the drive mechanism of the mixing device;

FIG. 7 a shows an exploded partial circuit diagram for the voltageregulator of the drive mechanism of the mixing device;

FIG. 8 shows a preferred circuit diagram for the drive mechanism of themixing device;

FIG. 8 a depicts an exploded partial circuit diagram for a pull-downresistor array in the drive mechanism of the mixing device;

FIG. 8 b shows an exploded partial circuit diagram for an open-collectorbuffer array in the drive mechanism of the mixing device;

FIG. 8 c illustrates an exploded partial circuit diagram for a firstpull-up resistor array in the drive mechanism of the mixing device;

FIG. 8 d shows an exploded partial circuit diagram for a transistoroutput array in the drive mechanism of the mixing device;

FIG. 8 e demonstrates an exploded partial circuit diagram for aHall-effect sensor array in the drive mechanism of the mixing device;

FIG. 8 f shows an exploded partial circuit diagram for a second pull-upresistor array in the drive mechanism of the mixing device;

FIG. 8 g depicts an exploded partial circuit diagram for a noise filtercapacitor array in the drive mechanism of the mixing device;

FIG. 8 h shows an exploded partial circuit diagram for a Schmitt-Triggerlogic buffer array in the drive mechanism of the mixing device; and

FIG. 8 i shows an exploded partial circuit diagram for a microprocessorin the drive mechanism of the mixing device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT AND OPERATION OF THEINVENTION

Turning now to the drawings for a better understanding of the preferredinvention and its method of operation, FIGS. 1-2 show preferred mixingdevice 10 which includes base 11 and drive mechanism 90. Drive mechanism90 is attached to base 11 and comprises brushless DC motor 51, motormount assembly 91 attached to motor 51 and pivotally attached to base11, turntable 70 with central shaft 77 rotationally attached to base 11and defining circular turntable groove 82, vertical motor shaft 22extending from motor 51 into turntable groove 82 and defining groove 22′with friction ring 81 affixed thereon for engaging and rotatingturntable 70, tilt assembly 20 pivotally attached turntable 70 that isrotatable thereunder and rigidly attached to platform 12 thereabove,platform 12 attached to base 11 by a plurality of flexible connectors13, and electrical circuitry including a pair of circuit boards attachedto base 11 and comprising power control circuit board A in electricalcommunication motor control circuit board B with microprocessor 110 inelectrical communication with motor 51 for managing the power suppliedthereto and the speed thereof to achieve and maintain manually selectedspeed received from potentiometer 230 serving as a manually adjustableincremental speed control switch through rotation of potentiometer shaft230′. As seen in FIG. 1, base 11 includes planar portion 14, which ispreferably metal and does not increase the size of the footprint ofmixing device 10, to which X-shaped base housing 15 is attached abovethereon and preferably comprises a polymeric material. While an X-shapeis preferred for the housing, any similar shape could be used such as aY-shape (not shown) or a V-shape (not shown), so long as corners areformed for allowance of a plurality of flexible connectors 13 to beattached thereon. Base housing 15 covers motor mount-assembly 91,circuit board A, and circuit board B and while turntable 70 is rotatablethereabove as seen in FIG. 2. Although not shown, planar base portion 14may have a plurality of standard elastomeric feet attached thereunderfor providing additional vibration reduction and positional stability ofmixing device.

As further seen in FIG. 2, platform 12 defines platform apertures 12′for receiving platform fasteners 32 and attaching to flexible connectors13 positioned thereunder. Platform fasteners 32 preferably compriseconventional Allen head bolts with cylindrical nuts 32′ whereby theheads of platform fasteners 32 engage platform 12 flush to the topthereof and the threaded shafts of platform fasteners 32 extend throughplatform apertures 12′ and threadably engage cylindrical nuts 32′pressure fitted within the tops of flexible connectors 13. Flexibleconnectors 13 are preferably transparent, flexible polyvinyl chloridetubing, although other standard flexible connectors could be used,either polymeric, natural or other spring materials. Raised knobs 14′(FIG. 3) are attached to planar base 14 and extend thereabove where theyare pressure fitted within the lower ends of flexible connectors 13 forattaching flexible connectors 13 to planar base portion 14. Conventionalslip ties (not shown) may be used to constrict flexible connectors 13 atthe top and bottom to provide clamping for increasing the frictionalengagement of pressure fitted platform fasteners 32 and raised knobs14′. Platform 12 is rigidly attached to the top of tilt assembly 20 asseen in FIG. 2.

Tilt Assembly 20 is a multi-component unit seen in FIGS. 2 and 4comprising pivot shaft 24 having pivot slot 74, threaded post 41defining threaded apertures 41′ on the top thereof, collar 23surrounding threaded post 41, a ball bearing (not shown), connecting rod71, and an internal spring (not shown) which rests on the floor ofcollar 23 and abuts the interior surface of threaded post 41 to preventany drift thereof during rotation. Collar 23 is preferably metal such asbrass and may have surface features (not shown) to improve gripexteriorly thereon. Collar 23 is interiorly threaded (not shown) forengaging threaded post 41 which permits threaded post 41 to be raised orlowered inside collar 23 as desired. Manual, selective clockwise orcounterclockwise rotation of collar 23 raises or lowers threaded post 41respectively therein. As seen in FIG. 2, threaded post 41 is rigidlyaffixed to platform 12 centrally positioned thereabove. Post fasteners35 extend down through platform apertures 12″ of platform 12 andreceived in apertures 41′ on the top of threaded post 41 therebelowwhereby fasteners 35 and apertures 41′ are preferably threadably matedand fasteners 35 engage platform 12 flush to the top thereof. The ballbearing (not shown) is preferably a 0.375 inch bore (0.953 cm) standardstainless steel ball bearing with pivot shaft 24 pressure fitted thereinand collar 23 rigidly affixed to the bearing for rotation about pivotshaft 24.

Turntable 70 preferably comprises a rigid disc of machined aluminumalthough other rigid materials may be used. As shown in FIGS. 4 and 5,turntable 70 includes top surface 78 and bottom surface 79 with circulargroove 82 along the circumference of bottom surface 79. Circular groove82 does not extend to top surface 78 as seen in FIG. 4. As shown inFIGS. 2 and 4, turntable 70 defines shouldered central aperture 70′ forreceiving vertical turntable shaft 77 secured therein by turntablefastener 75, and pivot channel 73 which is substantially oval in shapeand spaced from central aperture 70′ for receiving tilt assembly pivotshaft 24. Turntable pivot channel 73 is spaced from turntable aperture70′ and accordingly offset from the center of turntable 70 wherebyrotation of turntable 70 will allow tilt assembly 20 to wobble back andforth within turntable pivot channel 73 while tilt assembly 20 isattached to platform 12. Turntable 70 further defines opposing extensionchannels 73′ for receiving connecting rod 71, and fastener channels 76for receiving rod fasteners 72. Pivot channel 73 intersects and is incommunication with extension channels 73′ which are positionedtransverse the shorter axis thereof and open to bottom surface 79 ofturntable 70 as shown in FIG. 4. Fastener channels 76 are preferablythreaded in an orientation parallel with turntable 70's axis of rotationand spaced radially therefrom on either side of pivot channel 73 aboveextension channels 73′ and are accessible from below turntable 70. (FIG.5) As seen in FIG. 4 tilt assembly 20 is pivotally attached to turntable70 by pivot shaft 24 along connecting rod 71 which is secured andmaintained within pivot channel 73 by rod fasteners 72. Pivot shaft 24defines pivot slot 74 for receiving connecting rod 71 at a positionbelow top surface 78 of turntable 70 for preventing upward removal ofpivot shaft 24 from pivot channel 73. Connecting rod 71 is preferablylonger than the length of pivot slot 74 such that the ends of connectingrod 71 extend equally beyond pivot shaft 24 when received therein. Withconnecting rod 71 received by pivot slot 74, extension channels 73′receive the ends of connecting rod 71 as pivot shaft 24 is moved towardstop surface 78 of turntable 70 whereby such movement is limited byconnecting rod 71 internally engaging turntable 70 within extensionchannels 73′ and transversely intersecting pivot channel 73 along itsshorter axis. Connecting rod is attached within turntable 70 by rodfasteners 72 received by fastener channels 76. Rod fasteners arepreferably threaded to coincide with the preferred threaded fastenerchannels 76 and from below turntable 70 threadably engage therein. Theheads of rod fasteners 72 engage different ends of connecting rod 71extending into extension channels 73′ for maintaining the same withinturntable 70 and allowing tilt assembly 20 to pivot back and forththrough a vertical position along connection rod 71 in pivot channel 73and permitting platform 12 attached to tilt assembly 20 to tilt or yawduring rotation. Although not shown, fastener channels 76 may be sizedto terminate within turntable 70 rather than extending through topsurface 78 thereof provided rod fasteners 72 received therein engage andmaintain connecting rod 71 within turntable 70.

As further seen in FIGS. 4 and 5 turntable 70 includes vertical shaft 77which is centrally, rigidly attached through aperture 70′ by fastener 75and rotationally attached to planar base 14 at its lower end (not seen).Turntable shaft 77 is preferably a rigid machined aluminum rod definingaperture 75′ on its top end for receiving fastener 75. Fastener 75engages turntable 70 and is maintained flush therewith as seen in FIG.5. Turntable shaft 77 is received and rotatable within base housing 15(FIG. 2) through base housing aperture 15′ whereby turntable 70 isrotatable thereabove. In an alternate embodiment not shown, turntable 70and turntable shaft 77 may be combined and formed from one continuousrigid material rather than with separate combinable parts as shown.

As seen in FIG. 3, motor 51 is rigidly affixed to motor mount assembly91 which comprises arm 21, spring 86, and vertical pivot shaft 85. Motormount pivot shaft 85 is motor mount assembly 91 comprises arm 21 havingaperture 21′ for receiving spring 86. Spring 86 is a conventional springhaving looped ends and is attached at one end to spring aperture 21′ andat the opposite end to spring base mount 16′ of rotational stabilizingmember 16. Arm 21 is rigidly attached to pivot shaft 85 as shown in FIG.2. Although not shown, pivot shaft 85 is pivotally attached to planarbase portion 14 whereby arm 21 is pivotable above planar base portion 14through pivot shaft 85 for allowing motor 51 to move arcuately above andacross planar base portion 14 in a plane parallel thereto as seen bydirectional arrow 50 in FIG. 3. Motor 51 is rigidly attached to arm 21by threaded motor mount fasteners 52 shown in FIGS. 2 and 3 which arereceived within motor apertures 52′ of arm 21 and threadably engagethreaded motor channels (not shown) in motor 51 whereby the shafts ofmotor mount fasteners 52 extend through motor mount arm 21 into motor 51therebelow and the heads of motor mount fasteners 52 engage arm 21.Although fasteners are preferred, attachment via other means of rigidattachment such as welding is also contemplated.

Rotational stabilizing member 16 shown in FIG. 2 is preferably rigidlyattached to planar base 14 with fasteners (not shown) but may also bewelded thereto. Rotational stabilizing member 16 comprises an invertedU-shaped housing but other shapes, such as an opposingly open-endedrectangular box (not shown), that guide and stabilize rotatable elementsextending therethrough as discussed herein are also contemplated.

Rotational stabilizing member 16 shown in ghost form in FIG. 3 defines aturntable aperture (not shown) spaced from a pivot shaft aperture (notshown) through which turntable shaft 77 and motor mount pivot shaftfastener 87 are respectively received and rotatable therein. (FIGS. 2,3)Pivot shaft 85 is preferably a rigid vertical aluminum bar and isrotationally affixed to planar base portion 14 and rigidly attached toarm 21. Fastener 87 is rigidly affixed to pivot shaft 85 androtationally links the same to rotational stabilizing member 16 as itextends therethrough. (FIG. 2) Motor mount pivot shaft 85 is pivotallyattached at its lower end to planar base portion 14 such that motormount arm 21 is parallel to, positioned above and pivotable over planarbase portion 14. Motor mount spring 86 is attached to spring mount 16′on rotational stabilizing member 16 for providing an anchor from whichmotor mount spring 86 may be stretched for applying rotational tensionon motor mount arm 21 about motor mount pivot shaft 85. To allowturntable groove 82 to receive motor shaft 22, motor mount arm 21 mustbe rotated radially, inwardly in relation to turntable 70 about motormount pivot shaft 85. Rotational movement of motor mount arm 21 extendsmotor mount spring 86 and “spring loads” motor mount assembly 91. Thetension force created by stretched motor mount spring 86 pivots motormount arm 21 radially outward in relation to turntable 70 wherebyfriction ring 81 engages and maintains contact with turntable outergroove wall 84 and prevents motor mount spring 86 from returning to anunstretched state of rest. Motor mount 91 is preferably “spring loaded”prior to motor 51 receiving motor shaft 22.

Housing 15, seen in FIG. 2 includes aperture 15′ for receiving shaft 77and aperture 15″ for receiving motor shaft 22. Motor shaft 22 extendsthrough and is rotatable therewithin and is centrally rigidly attachedto motor 51 at its lower end through arm shaft aperture (not shown) inarm 21. Motor shaft 22 defines groove 22′ towards its upper end forreceiving friction ring 81 which is pressure fitted thereon. Frictionring 81 is preferably a durable resilient inert polymeric material andmay be comprised of one or a plurality of rings. As seen in FIGS. 4 and5, turntable 70 includes circular groove 82 having inner wall 83 andouter wall 84 and opens to bottom surface 79 of turntable 70. Turntablegroove 82 receives motor shaft 22 whereby friction ring 81 engages outergroove wall 84. When motor shaft 22 is rotated by motor 51, frictionring 81 preferably rotates without slippage on motor shaft 22 andagainst turntable outer groove wall 84 which imparts a frictional force(not shown) thereon that is substantially tangential to the central axisof turntable 70 whereby turntable 70 is driven to revolve around itscentral axis along vertical shaft 77.

As turntable 70 is rotated, tilt assembly 20 pivots in pivot channel 73thereby causing collar 23 to rotate thus rotating platform 12 therewith.This movement causes platform 12 to circumscribe an eccentric orbit overbase 11 since the center of platform 12 is not directly above the centerof base 11. Threaded post 41 can be manually raised and lowered withincollar 23, thus changing the distance between platform 12 and base 11.Since tilt assembly 20 is rotating, threaded post 41 has a tendency to“drift” downwardly on the internal threads of collar 23, thus changingthe positioning of platform 12. The coil spring (not seen) in tiltassembly 20 is tensioned between collar 23 and threaded post 41 andcorrects this “drifting” by biasing threaded post 41 so that threadedpost 41 does not rotate downwardly within collar 23 as turntable 70moves in its circular path. As threaded post 41 is lowered within collar23, more tension is put upon the coil spring (not shown) of tiltassembly 20.

The ability to raise and lower threaded post 41 and platform 12 isimpacted by the shape and positioning of tubular flexible connectors 13.When platform 12 is raised to the maximum, flexible connectors 13 aregenerally straight and undistorted. When turntable 70 is rotated andtilt assembly 20 swings platform 12 in its orbit over base 11, each armremains essentially straight and platform 12 remains level. Thus, abiological/chemical solution can be mixed via a horizontal swirlingmotion with little or no vertical agitation. However, when platform 12is lowered, flexible connectors 13 are distorted and compressed intonon-linear shapes. As platform 12 is rotated, each flexible connector 13in turn is straightened. The corresponding corner of platform 12 israised to its highest point above base 11 when its flexible connector 13is straight. The remaining corners of platform 12 are in varying degreesof straightness closer to base 11, with the opposite corner generallybeing the lowest position. Flexible connectors 13 associated with theselowered corners are distorted into non-linear shapes, the amount ofdistortion being generally inversely proportional to the height of thecorresponding corner above base 11. The lower platform 12 is selectivelypositioned, the greater the tilt thereof. Thus, manual rotation ofcollar 23 raises and lowers platform 12 to allow selection of the degreeof tilt of platform 12. The tilting of platform 12 along with theorbital path that platform 12 circumscribes causes both horizontal andvertical agitation of solutions placed thereon. Therefore, selectiveadjustment to the degree of tilt of platform 12 allows the choice of thevertical agitation induced into the solution during use of mixing device10. A commercially available rubberized non-slip pad (not shown),preferably a resilient polymeric material having an irregular surface,can be placed on the top of platform 12 so as to provide additionalfrictional engagement and prevent items such as beakers, dishes or othercontainers (not shown) from sliding along tilted platform 12.

As would be understood, mixing device 10 must be in electricalcommunication with an electric power source in order to function. Poweris supplied to mixing device 10 as illustrated in FIG. 3 throughstandard power cord 95 which is in electrical communication with powercontrol circuit board A at connector P4. Power control circuit board Acleans the potentially poorly regulated and unstable plurality ofelectric currents and voltages supplied to mixing device 10 and convertsthe current into +12 VDC. Motor control circuit board B seen in FIG. 3is in electrical communication with power control circuit board A viawire harness D and potentiometer 230 which operates as a manual speedcontrol switch for selectively setting desired rotational speed of motor51. Line operated switch-mode power supply circuit 300, contained onpower control circuit board A of mixing device 10, is depicted inschematic form in FIG. 6. Power supply circuit 300 will accommodate bothdomestic 120 VAC and foreign 250 VAC at 60 Hz and 50 Hz to operatedevice 10 without necessitating circuit reconfiguration. AC line voltageis supplied to power supply circuit 300 at interface 301 with connectorP4 while AC ground voltage and AC neutral voltage are linked to powersupply circuit 300 at interfaces 302 and 303 respectively with connectorP4. Fuse 310, preferably rated 0.250 AMP—240 VRMS, protects power supplycircuit 300 against over-current and risks of fire, while standard metaloxide varistor 320 prevents circuit damage from input voltagetransients. Common-mode configured transformer 330, which is preferablymodel CTX300-4 by Coiltronics Inc. available from Bravo ElectroComponents, Inc. of Santa Clara, Calif. and rated 1.6 mH, and itspreceding capacitor 331 protect power supply circuit 300 from highfrequency noise. Capacitor 331 is preferably rated 0.22 μF—275 vac.Bridge rectifier 340 converts the supplied AC line voltage intounregulated high-voltage DC which is filtered by capacitor 341 andsubsequently presented to primary windings 355 of high-frequencytransformer 350, preferably model XF0013-EPD20S by XFMRS, Inc. of Camby,Indiana, whereby leading-edge voltage spikes caused by transformer 350inductance leakage are clamped between diodes 342 and 343. Switchingregulator 370, preferably part number TOP224Y manufactured by PowerIntegrations, Inc. of San Jose, Calif., then modulates the unregulatedhigh-voltage DC within high-frequency transformer 350 via pulse-widthmodulation at a high frequency. Switching regulator 370 interacts withpower supply circuit 300 with connections including drain pin 373,common pin 374, and source pin 375. Energy driven into high-frequencytransformer 350 appears on its output power windings 360. Transformerbias winding 365 is rectified and filtered by diode 366 and capacitor367 to create a bias voltage to be used by switching regulator 370 toconvert voltage to desired +12 VDC output. Optocoupler 380, preferablyconsisting of a standard gallium arsenide infrared emitting diode (notshown) driving a silicon phototransistor (not shown) in a 4-pin dualin-line package (not shown) such as part number H11A817A produced byFairchild Semiconductor Corporation of South Portland, Me., feeds theamplitude back to switching regulator 370 through an electricallyoptically isolated path. Switching regulator 370 is able to drive intotransformer 350 the precise amount of energy necessary through secondarypower windings 360 to produce +12 VDC output voltage at interface 304with connector P5 on power control circuit board A, once rectified bydiode 361 and filtered by capacitors 362 and 363. Power supply circuit300 is returned to ground at interface 305 with connector P5 on powercontrol circuit board A. The +12 VDC output voltage created by powersupply circuit 300 at interface 304 is determined by a combination ofthe voltage of Zener diode 381 and voltage drops across optocoupler 380and resistor 382. Resistor 383 and Zener diode 381 improve the loadregulation at light loads by providing a slight pre-load on the +12 VDCoutput. Capacitor 364 serves to bypass high frequency noise whilecapacitor 371 and resistor 372 compensate feedback loop for voltageregulation leading into switching regulator 370. Power supply circuit300 preferably comprises components with the following ratings:capacitor 341 rated 100 UF—450V—20%; diode 342 rated 200V—600 W Peak;diodes 343, 361 and 366 each rated 600V; capacitors 363 and 367 eachrated 0.1 UF—50V—10%; capacitor 363 rated 470 μF—25V—20%; capacitor 364rated 1000 PF—250V—10%; capacitor 371 rated 47 UF—20V—20%; resistor 372rated 6.810 HM—¼ W—1%; Zener diode 381 rated 1.5 W/11V; resistor 382rated 1000 HM— 1/10 W—1%; and resistor 383 rated 2210 HM— 1/10 W—1%.

FIG. 7 shows an electrical schematic for +12 VDC to +5 VDC voltagesub-regulator circuit 400 contained on motor control circuit board B ofmixing device 10 for driving microprocessor 110 (FIG. 8). Motor controlcircuit board B receives a current of +12 VDC of potentially poorregulation and stability which is supplied to voltage sub-regulatorcircuit 400 at interface 403 with connector P3 on motor control circuitboard B. Voltage sub-regulator circuit 400 is sourced to ground atinterface 404 with connector P3 on motor control circuit board B.Interface 420 is +12 VDC to be used by motor control circuit board B.Loading resistors 410-411 are employed at input of voltage sub-regulatorcircuit 400 to present a minimal load at all times for maintainingstability of the upstream line operated power supply 300 whilecapacitors 412-418 of various size and characteristic are employedbefore and after standard voltage regulator 430 to remove noise and toimprove stability. +12 VDC is inputted into voltage regulator 430 atinput 431 (FIG. 7 a). Voltage regulator 430 maintains stable and precise+5 VDC output at output 432 provided a sufficient voltage margin above+5 VDC is maintained at input 431. Voltage regulator 430 is lead toground through outputs 433-436. Voltage sub-regulator circuit 400outputs to motor control circuit board B +5 VDC at interface 401 and toground at interface 402 which is used by microprocessor 110. Voltagesub-regulator circuit 400 preferably comprises components with thefollowing ratings: loading resistors 410-411 rated 1.00K—⅓ W—1%;capacitors 412, 414, and 416-417 each rated 0.1 UF—50V—10%; capacitor413 rated 470 UF—25V—20%; capacitors 415 and 418 each rated 10 UF—20V 010%.

FIG. 8 is a partial electrical schematic of motor control circuit boardB for managing preferred three-phase brushless DC motor 51 with integralHall-effect sensor feedback array 170 schematically depicted in FIG. 8 eof mixing device 10. Motor 51 functions are controlled by microprocessor110, preferably an 8-bit Motorola USMC68HC908MR8CDW microprocessor,comprising pulse-width modulation (“PWM”) module 120 with pre-programmedapplication software-implemented functions (not shown) providing (1) acompensated feedback algorithm to effect precise speed control includingcompensation of the effects of mechanical inertia and loading, and (2) avirtual power switch that eliminates routing line voltage carryingconductors to a combination potentiometer-switch assembly which keepsvoltage low. FIG. 8 e schematically illustrates microprocessor 110 andshows connecting pins referenced thereon.

PWM module 120, which includes output pins 121-126, regulates the energysent to motor 51 to control rotational speed of motor shaft 22 forachieving desired speed corresponding to the manually selected setpoint. Each sensor in Hall-effect sensor array 170 monitors a separatephase of motor 51's three-phase stator windings 167-169 whereby phaseone 167, phase two 168 and phase three 169 are monitored by Hall-effectsensors 175, 174, and 173 respectively. Hall-effect sensors 173-175,shown schematically in exploded form in FIG. 8 e report back tomicroprocessor 110 the precise angle of motor shaft 22 at each one ofmotor 51's three-phase stator windings 167-169 whereby the feedbackpulses from Hall-effect sensor array 170 are proportional to therotational speed of motor shaft 22. Microprocessor 110 uses thesefeedback pulses to adjust the timing of the electronic commutation ofmotor 51 through each phase of its three-phase stator windings 167-169to achieve rotation and maintain user selected rotational speed.

Internal clocking of microprocessor 110 is effected by 4 MHZ quartzcrystal oscillator 210 with associated loading capacitors 211 and 212and bias resistor 213, while a phase frequency-locked-loop (not shown)within microprocessor 110 multiplies the frequency of crystal oscillator210 into a higher clock rate. Crystal oscillator 210 and thephase-locked-loop (not shown) are part of the clock generating module(“CGM”) (not shown) of microprocessor 110. Crystal oscillator 210receives input from microprocessor 110 at pin 214 and returns outputthereto at pin 215. External filter capacitor 281 filters out phasecorrections for the CGM (not shown) and is connected to microprocessor110 at pin 280. Loading capacitors 211 and 212 are preferably each rated22 PF, 100V and 5%. Bias resistor 213 is preferably rated 10M— 1/10W—5%. Power-on reset 220 of microprocessor 110 is effected by a timeconstant derived by charging reset delay capacitor 222 and filtered byresistor 221 or alternatively forced externally via connector P1. Motorcontrol circuit board B is pre-programmed with standard and applicationspecific software for functionality of microprocessor 110 containedthereon. Application specific software includes algorithms (not shown)to process the effect of loading platform 12 on the rotational speed ofmotor shaft 22 as well as power management of device 10 previouslydiscussed. The application specific software is based on a standardproportional integral derivative commonly used for electroniccommutation of motors however the derivative is not used since velocityis variable and not linear. The application specific software andmodifications thereto is loaded into microprocessor 110 at connector P1by activating reset pin 251 while IRQ pin 256 is held at logic zeroallowing serial communications with microprocessor 110 via datatransmitting pin 252 and data receiving pin 253. Resistors 253, 255, and257 filter the current in communication with microprocessor 110.Additionally, for production purposes, multiple microprocessors may beprogrammed simultaneously before affixed to motor control circuit boardB with a standard chip programmer whereby each microprocessor is pluggedinto a separate socket of the programmer and the application specificsoftware is loaded into the flash memory of each loaded microprocessorat the same time. With application software resident and running,microprocessor 110 derives the digital representation of the shaftposition of potentiometer 230 via an internal 10-bit analog-to-digitalconverter (“ADC”) peripheral (not shown). Potentiometer 230 acts as aspeed control input device by serving as a simple voltage dividerbetween ground and +5 VDC when potentiometer shaft 230′ is fullycounterclockwise or fully clockwise respectively. FIG. 8 i schematicallyrepresents an exploded view of the pin connections for microprocessor110. Microprocessor 110 operates from a single power supply and receives+5 VDC at power supply pins 260 and 262 and is sourced to ground at 261and 263, whereby pins 262 and 263 are the power supply and ground pinsfor the analog portion (not shown) of microprocessor 110 including theCGM (not shown) and the ADC peripheral (not shown). Pin 265 is the powersupply input for setting a reference voltage used by microprocessor 110particularly in the ADC peripheral (not shown). Pins 266 is a 7-bitgeneral-purpose bidirectional I/O port that is shared with the serialcommunications interface module (not shown). Pin 267 is a 2-bit specialfunction I/O port shared with PWM 120. Capacitors 222, 233, and 281 arepreferably each rated 0.1 UF—50V—10%. Resistors 221, 253, 255, and 257are each rated 47K— 1/16 W—5%.

The preferred method of mixing closely follows the function of thedevice described herein. Agitation is initiated and controlled by manualselection of the desired mixing rate which is implemented by electroniccommutation of motor 51 for rotation of motor shaft 22 and movement ofthe elements connected thereto. After device 10 is in electricalcommunication with a power source through interfacing with standardelectric power cord 95 at connection P4 on power control circuit boardA, the power supplied is converted as necessary by power control circuitboard A through switch-mode power supply circuit 300 contained thereonto produce and output +12 VDC to motor control circuit board B via wireharness D interfacing connector P5 and P3 respectively. Voltagesub-regulator circuit 400 on motor control circuit board B where it isreduced to +5 VDC for driving microprocessor 110 and increased back to+12 VDC for driving motor 51. Microprocessor 110, with +5 VDC suppliedthereto at pin 260, compares voltage input from potentiometer 230, whichis filtered by resistor 232 and capacitor 233 and digitally representsthe rotational position of potentiometer shaft 230′, to the programmedvoltage range to determine the desired manually selected rotationalspeed of motor shaft 22. Resistor 232 is preferably rated 10K. Upon apartial clockwise rotation of potentiometer shaft 230′ from the fullycounterclockwise position, a change in voltage from potentiometer 230results and is recognized by microprocessor 110 at pin 231. If thevoltage input from potentiometer 230 exceeds a pre-programmed threshold,microprocessor 110 reacts to voltage change and sends output current onLED pin 243 and driven by transistor 242, which is a general-purposeperipheral pin, through filtering resistor 241 to display LED 240 whichilluminates display LED 240 for rendering a virtual “on” state. Theillumination of display LED 240 depicts a virtual “on” state becausemixing device 10 is only “off” when it is not in electricalcommunication with an electric power supply. Resistor 241 is preferablyrated 2.21K—⅓ W—1%.

Drive of the stator windings of motor 51 is effected via output frommicroprocessor 110 at output pins 121-126 corresponding to PWM module120. Pull-down resistor array 130, which is comprised of resistors131-136 shown schematically in exploded form in FIG. 8 a, insures aknown drive state as microprocessor 110 initializes or if microprocessor110 fails. The output from pull-down resistor array 130 is subsequentlybuffered by open-collector buffer array 140 via buffers 141-146 andresistors 141′-146′ shown schematically in exploded form in FIG. 8 b.Since microprocessor 110 is driven by +5 VDC and motor 51 is driven by+12 VDC, open-collector buffer array 140 additionally serves totranslate the +5 VDC logic level of microprocessor 110 to +12 VDC. Firstpull-up resistor array 150, comprising resistors 151-156 shownschematically in exploded form in FIG. 8 c and preferably each rated1.00K—⅓ W—1%, serves to source +12 VDC to transistor output array 160through transistor pairs 161-162, 163-164, and 165-166 shownschematically in exploded form in FIG. 8 d. Transistor output array 160in turn switches +12 VDC to motor 51 in such fashion that the lead toeach phase of three-phase stator windings 167-169 is driven to either DCground, +12 VDC, or be left floating, for effecting electroniccommutation of motor shaft 22. Motor 51 is connected tothree-phase-configured stator windings 167-169 and Hall-effect sensors173-175 through interfacing with connectors P2 and J2 wherebyHall-effect sensors 173-175 are powered with +5 VDC and led to ground at171 and 172 respectively as shown schematically in exploded form in FIG.8 e. Hall-effect sensors 173-175 detect the instantaneous shaft angle ofmotor 51 and are pulled to logic +5 VDC via second pull-up resistorarray 180 via resistors 181-183 shown schematically in exploded form inFIG. 8 f. The resulting feedback logic level voltage from Hall-effectsensors 173-175 which is a digital representation of the position ofmotor shaft 22 passes through resistors 184-186 before noise is filteredby noise filter capacitor array 190 by capacitors 191-193 shownschematically in exploded form in FIG. 8 g and preferably each rated 470PF—100V—5%. Next, the cleaned feedback current passes through resistors194-196 and is buffered by Schmitt-Trigger logic buffer array 200through buffers 201-203 and 201′-203′ shown schematically in explodedform in FIG. 8 h. The buffered feedback current comprising the states ofHall-effect sensors 173-175 is then presented to microprocessor 110redundantly at pins 273 & 273′, 274 & 274′, and 275 & 275′ respectively.Microprocessor 110 calculates the instantaneous rotational speed ofmotor shaft 22, which is a function of the instantaneous shaft angles ofmotor 51 digitally represented by the feedback current. Microprocessor110 then compares the instantaneous speed of motor shaft 22 to thedesired manually selected speed computed from digital representation ofthe potentiometer shaft 230′ and determines and outputs the necessarytiming and switch voltage presented to motor 51 for electroniccommutation thereof to reach desired rotational speed of motor shaft 22.Resistors 131-136, 141′-146′, 181-186, and 194-196 are preferably eachrated 10.K— 1/10 W—1%.

As motor shaft 22 is rotated about its central axis, friction ring 81preferably rotates at the same rate as motor shaft 22. Rotation offriction ring 81, imparts a tangential force on turntable groove outerwall 84 and turntable 70 rotates about its central axis on turntableshaft 77. As turntable 70 spins, tilt assembly 20 traces an orbit aboutturntable shaft 77 whereby ball bearing (not shown) rotates about pivotshaft 24 which keeps threaded post 41 from rotating about its owncentral axis. As threaded post 41 is moved around turntable shaft 77,platform 12 follows the same orbit. The tension and compression forcesplaced on flexible connectors 13 change as tilt assembly 20 rotatesabout turntable shaft 77 which alters the degrees of straightness offlexible connectors 13 and tilt assembly 20 wobbles back and forth inturntable pivot channel 73 whereby platform 12 tilts or yaws in relationto the movement of tilt assembly 20. As the speed switch is manuallyselectively rotated clockwise or counter-clockwise, the degree ofvertical and horizontal movement of platform 12 increases or decreasesrespectively.

In an alternate embodiment (not shown) microprocessor 110 is alsopre-programmed with software for current overload protection of motor 51whereby as loading of platform 12 exceeds the capabilities of motor 51to achieve the selected speed and microprocessor 110 will continue tosend more current to motor 51 to compensate, microprocessor 110implements a fallback in power to motor 51 before trying again to sendcurrent once the pre-programmed motor current threshold is reached in aneffort to prevent motor damage. Additionally, the functionality ofcircuit board A and circuit board B may be combined on a single board(not shown) or further distributed to additional circuit boards (notshown).

Capacitors 341, 371, and 362 and capacitors 413, 415, and 418 arepolarized and illustrated schematically with a plus-sign “+” designatingthe positive lead thereof in FIGS. 6 and 7 respectively.

Components set forth above and in the Figs. herein for mixing device 10have the following model numbers and are commonly available from manymanufacturers: COMPONENTS OF MIXING DEVICE 10 MODEL NUMBERS buffers141-146 ULN2003L transistors 161-166 QSIRF7319 buffers 201-203 and201′-203′ MC74HCT14AD potentiometer 230 51AADB24A15 display LED 240HLMP-1521 transistor 242 2N7002 metal oxide varistor 320 V390ZA05 bridgerectifier 340 DF1506S diode 342 DF1506S diodes 343, 361, and 366MURS160T3 optocoupler 380 H11A817AS Zener diode 381 1SMA5926BT3 standardvoltage regulator 430 USMC78L05_SO8

A commercially available standard assembler program (not shown)compatible with microprocessor 110 is used to convert the source code ofthe application specific software into machine language whichmicroprocessor 110 can interpret, commonly referred to as “S-records”(not shown). The S-records are loaded into microprocessor 110 forprogramming the same with the application specific software as describedherein. The source code of the application specific software forpreferred mixing device 10 is as follows:

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

The illustrations and examples provided herein are for exploratorypurposes and are not intended to limit the scope of the appended claims.

1.-20. (canceled)
 21. A drive mechanism for a mixing device comprising:a motor, electrical circuitry, said electrical circuitry comprising amicroprocessor, said motor connected to said electrical circuitry, amotor shaft, said motor shaft joined to said motor, a turntable, saidturntable defining a circumferential groove, said motor shaft engagingsaid circumferential groove for rotating the same.
 22. The drivemechanism of claim 21 further comprising a motor mount assembly, saidmotor mount assembly attached to said motor.
 23. The drive mechanism ofclaim 21 wherein said motor shaft defines a groove.
 24. The drivemechanism of claim 23 further comprising a friction ring, said frictionring positioned in said motor shaft groove.
 25. The drive mechanism ofclaim 22 wherein said motor mount assembly is spring loaded.
 26. Thedrive mechanism of claim 21 further comprising a speed switch, saidspeed switch connected to said electrical circuitry.
 27. The drivemechanism of claim 21 wherein said motor shaft is positioned in saidcircumferential groove.
 28. The drive mechanism of claim 27 furthercomprising a turntable shaft, said turntable shaft attached to saidturntable centrally thereof.
 29. The drive mechanism of claim 27 whereinsaid circumferential groove comprises an inner and an outer groove wall,a friction ring, said friction ring mounted on said motor shaft, saidfriction ring engaging said turntable outer groove wall.
 30. A method ofmixing utilizing a turntable and a rotatable platform connected by atilt assembly controlled by electrical circuitry including amicroprocessor and a motor comprising the steps of: a) supplying powerto the electrical circuitry; b) placing a solution to be agitated on theplatform; c) selecting a desired mixing speed; d) interpreting theselected mixing speed by the microprocessor; and e) mixing the solutionby rotation of the platform by the motor at the interpreted speed. 31.The method of claim 30 wherein mixing the solution further comprises thestep of driving the turntable with the motor and rotating the tiltassembly to cause the platform to orbit.
 32. The method of claim 30wherein supplying power to the electrical circuitry further comprisesthe step of supplying A.C. power.
 33. The method of claim 30 whereinplacing a solution to be agitated further comprises the step of placinga biological solution on the platform.
 34. The method of claim 30wherein selecting a mixing speed further comprises the step of managingthe motor speed through using a motor controlled circuit board.
 35. Themethod of claim 30 wherein interpreting the selected mixing speedfurther comprises the step of directing the electronic communication ofthe motor.
 36. The method of claim 30 wherein mixing the solutionfurther comprises the step of agitating the solution by vertical andhorizontal movement of the platform.
 37. A method of mixing a biologicalor chemical solution utilizing a turntable and a rotatable platformcontrolled by electrical circuitry having a preprogrammed microprocessorand a motor comprising the steps of: a) supplying power to theelectrical circuitry to drive the microprocessor to exceed a selectivevoltage; b) rotating the motor; c) exerting a force from the motor tothe turntable; and d) orbiting the platform to thereby mix a solutionplaced thereon.
 38. The method of claim 37 wherein exerting a forcefurther comprises the step of exerting a force from a motor shaft to theturntable.
 39. The method of claim 37 wherein orbiting the platformfurther comprises the step of driving a tilt assembly attached to theturntable.
 40. The method of claim 39 wherein driving the tilt assemblycomprises the step of tilting the platform for both horizontal andvertical agitation to the solution.